Multiple glass top fuse plug



Feb 27, 1934- c. l. JUsTHElM MULTIPLE GLASS TOP FUSE'PLUG 2 Sheets-#Sheet l Filed NOV. 17, 1931 Feb. 27, 1934. C, JUSTHElM 1,949,016

MULTIPLE GLASS TOP FUSE PLUG Filed Nov. 17, 1931 2 Sheets-Sheet 2 Patented Feb. 27, 1934 UNITED STATES PATENT OFFICE Application November 17, 1931 Serial No. 575,529

4 Claims.

elements turned into use.

A further object is to provide a simplified construction for multiple fuse plugs in which glass is used as the cover therefor so that all of the elements are visible at all times and also so that the person looking at the fuse may readily ascertain which element is being used at the time.

A still further object is to provide an economically constructed fuse plug having six fuse elements therein any one of which may be used to carry the current and which may have the glass top thereof rotated to change from one fuse element to another.

A still further object is to provide a fuse plug having several fuse elements made into an internal fuse but so formed that only one single element may be used at a time and so that the glass top may be rotated to turn a new element into contact when one element has been blown out by a short circuit or an overload and also to provide a plug which is cheaper to manufacture and more efficient than those heretofore placed on the market.

These objects I accomplish with the device illustrated in the accompanying drawings in which similar numerals and letters of reference indicate like parts throughout the several views and as described in the specification forming a part of this application and pointed out in the appended claims.

In the drawings in which I have shown the best and most preferred manner of building my invention,

Figure 1 is a vertical diametrical section of the device.

Figure 2 is a plan view of the fuse.

Figure 3 is a diametrical section of the glass cover for the fuse with the fuse elements removed.

Figure 4 is a plan View of Figure 3.

Figure 5 is a plan view of the fuse elements.

Figure 6 is a partial view of the spring contact between the fuse element and the screw base of the plug showing the means used to prevent rotation of the cover in the wrong direction.

Figure 7 shows a means of securing the glass cover to the base.

Figure 8 is an inverted plan view of a modied form of making the fuse and plug in which the fuse elements are formed radially within a ring but not engaging medially therein as in the other forms and having the central shift from one element to the other.

Figure 9 is a vertical section on line 9 9 of Figure 8.

Figure 10 is a section of the cover or rotatable glass top for the fuse shown in one ilat piece (Cl. 20G-125) with a metal ring to hold it to the ange on the base.

Figure 11 is a section of the glass plate alone.

Figure 12 is a plan view of the plate with the fuse element in place therein.

Figure 13 is a vertical diametrical section of still another modified form of making the fuse in which the glass cover rotates the central contact to make the contact with the separate fuse elements and in which the fuse elements are carried in the base and are stationary.

Figure 14 is a plan view of the base showing the fuse element in place therein.

Figure 15 is an inverted view of the glass cover shown on Figure 13.

Figure 16 is a side elevation of the rotatable contact.

Figure 17 is a section of one corner of the cover and base showing the use of a metal ring around the groove of the flange to allow the glass to slide thereover and to prevent the glass from sticking when it is heated and crimped in around the flange.

In the drawings I have shown the base of my device as A, having a medial hole 1 therein in which the central contact B of the device is carried. The bottom end 2 of the base is formed with external threads 3 therearound and over which I place the screw thread brass contact base 4.

An opening 5 is formed in one side of the base having the top end of the hole vat the top of the base A formed longer and in which hole the contact 6 of my device is placed with the lower end 7 thereof soldered to the brass base 4. The top end of the contact 6 is formed at right angles thereto and is then bent back upon itself but spaced apart with the end formed into a contact and locking lug 8. The medial spring contact B is formed of a spring 9 having a lug 10 placed through a hole in the base passing down through the base from the hole 1. The end of the lug is open and a socket contact plug 11 is driven thereinto to form a central contact on the bottom end of the base and to form a means of locking the central contact securely in place in the hole 1. The top end of the contact B is bent over and formed into a semi-spherical contact 12. The outer perimeter of the base A is formed with facets to make insertion thereof into a socket more easy. The top of the base A is provided with a Flange 15 thelearound to provide means to hold a glass cover C thereon. The glass cover C is formed of one casting having the bottom face provided with radial grooves 16 therein in which the fuse elements are carried and the ends of the grooves will be provided with slanting sockets 1'7 into which the ends of the fuse elements may be secured either when the glass is still warm or by any suitable cement to hold the contacts therein. A central hub 18 is formed on the bottom of the cover over which the medial hub portion of the fuse element is fitted before tting the separate elements into their respective grooves and the end of the hub is formed concave at 19 to allow the hub of the fuse to be so formed and to have the semi-spherical contact 12 fit t-hereinto to make a constant contact therewith at all times by the spring pressure of the contact B. rThe cover C is formed of a plate having an annular flange 2O adapted to fit down around the flange 15 and then have the lower end of the flange heated and curved inwardly locking the cover to the base. One edge of the radial slots or grooves into which the fuse elements are placed is cut with a sloping acute angle so that the end lug 8 of the fuse contact 6 will engage therewith preventing the cover from rotation in the wrong direction. On the top outer side or the cover C in iiteen amperage fuses I form a hexagonal depression 22 to meet the requirements of the re underwriters and in higher voltage fuse elements I form a depression shaped also to conform with the requirements of the same body.

The fuse element D is formed with a hub 25 having radially extending elements extending therefrom the said elements being provided with a hub engaging portion 26, blow out thin portions 27 and broader contact portions 28.

The fuse elements are placed in the cover and secured therein as heretofore described, the cover is placed on the base and held down thereto while the edges are crimped in to hold it thereon. This brings the hub of the contact into contact with the medial contact B of one of the portions 28, into contact with the end 8 of the contact 6, completing the circuit from the brass base 4 through the contact 6, one segment or element of the fuse through the contact portion 28, the thin portion 27 and the hub portion to the hub and thence through the contact B to the end of the socket contact plug 11. As shown in Figure 7 the edges of the flange of the cover do not need to be turned in but separate plugs or rods 30 of metal may be inserted through holes near the lower edge of the iiange to engage with the ange l5.

In Figures 8 and 9, I have shown the use of a rotating coverEheld onto the ilange 31 of the base F by an annular ring 32 having the top formed with a ange to engage over the cover and having the bottom crimped in under the edge of the ange. Into the cover E, I then place the fuse element H which element is made of a ring 33 having inwardly extended radial fuses 34 said fuses having the blow out portion 35 thinner than the ring or the contact portions 36. The contacts 36 do not touch each other but are spaced apart suicient to prevent arcing therebetween when one fuse is blown. I then provide a contact spring 3'? engaging onto the face of the ring 33 with the end of the spring engaged through a socket or opening 37a to the screw thread brass base 88. The central contact of the device is made of a spiroidal spring contact 39 having the bottom eno'. secured to the medial contact 40 and having a contact 41 formed on the top end to engage by spring pressure with the contacts 36 of the fuse H. This completes the circuit and when the fuse elements have blown out the operator may then rotate the cover engaging the spring il with the next element 36 in the rotation around the axis.

In Figures l0, 11 and 12, I have shown the making of the cover for use in the type shown in Figure 1 of a plate of glass 43 having the fuse elements carried therein in formed sockets 44. The central portion of this type element has a concave hub therein but does not have any depending hub on the glass. The central contact fitting up higher in the base. This type of plate is secured to the base by an annular ring of metal 45 having the top side hanged at 46 to engage over the glass and having the bottom edge crimped under the iiange or" the base to hold the plate thereon. A depression in the glass and in the ring will hold them to rotate simultaneously. The top side of the glass is provided with a hexagonal depression therein to designate that that particular type of fuse is able to carry a load of l5 amperes. For other types the shape of the depression will be changed to conform to the nre underwriters association regulations.

In Figure 13, I have shown a still further type of modification in which the base K is made with i a depression 48 therein into which the fuse element 49 is set. The fuse element 49 is made similar to the one shown in Figure 8, with an annular ring 50 having inwardly extended radial elements 51 of a thinness sunicient to blow out at the required load and having the end contacts made larger at 52. The edge of the ring has a permanent member 53 secured to one side thereof said contact member being also secured to the brass thread 54 on the base K. Medially in the base I provide a socket or opening 55 in which a vertical contact 55a is carried, said contact having the bottom end flattened out on the bottom side of the base to make the central contact of the fuse, and the top end of the contact is carried in a medial boss 57a in the glass 57. The boss has a locking bar or rod 58 passed through the boss and the contact bar to hold them together, and under the boss I provide a flange contact 59 which contact is carried on the contact post 55a and has one side provided with a radially extended spring contact 60 which contact has the end bent back upon itself but spaced therefrom to contact the end of the fuse element as it rotates by rotating the cover.

As shown in Figure 17 the central contact post 55a may be provided with a ball and socket joint 62 therein to allow for rotation of the post with the cover without rotating the central contact on the outside of the base. The cover of the device is shown as a flanged plate of glass 57 having securing rods passed through the ange after it has been placed over the base to hold the cover to the base.

In Figure 18, I have shown a metal ring 63 fitted in the groove under the flange of the base to prevent the glass from adhering to the flange or groove when it is heated and crimped in around the flange as shown.

Having thus described my invention I desire to secure by Letters Patent and claim:-

l. In a fuse plug the combination of a base; a threaded screw contact screwed thereon; a central spring contact through the middle of said base in an opening therein; a semi-spherical contact on the top end of said spring contact; a spring contact through an opening in one side of said base with the end secured to the screw contact; a solid glass cover adapted to nt in a flange around the top of said base, said cover having depressions therein in which the fuse elements are carried; a fuse element carried in said depressions said element being formed of individual radial fuse elements having a thin blow out portion therein all attached to a comicfmon hub, said hub being fitted onto a hub within said glass cover and adaptedto engage the semispherical portion of the centralbase contact; sloping sockets in which the ends of the fuse elements are secured; and means to secure the edge of a ange on the glass cover around the ange on the base to hold the two together.V

2. In a fuse plug the combination of a base having a central contact carried therein and a spring contact carried in one side thereof, said side contact being secured to a brass sheet over the bottom of said base; a solid glass cover for said base carrying radial fuse elements said elements to be brought into contact with the side spring contact by rotation of the glass cover and to be in constant contact with the central contact and means by the spring contacting the side of the base to contact the grooves in which the fuse elements are carried to prevent rotation in one direction and allow rotation in the opposite direction.

3. In a fuse plug of the class described the combination of a solid glass fuse carrying element carrying radial fuse elements around a common hub; a base on which said glass is carried; means to secure the cover to the base; a central contact through said base in spring contact with the hub of the fuse elements; a side spring contact having the engaging portion bent in one direction to engage said radial contacts when the glass is rotated and to engage the glass in the grooves carrying the fuse elements in the glass to prevent rotation in one direction.

4. In a fuse plug of the class described, the

combination of a base having a medial hole therein; a threaded screw contact screwed thereon; a central contact spring through thev bottom of said base and extending up through the hole therein; a semi-spherical contact on the top end of said vspring contact; a spring contact through an opening in one side of said base secured to the screw contact; a fuse engaging contact and locking lug formed on the top end of the spring contact by bending one portion at an angle to the spring contact and bending the end thereof back upon itself to make the contact and locking lug; a solid glass cover for said base to t thereon said cover having radial depressions therein terminating in sloping sockets near the perimeter of said cover and a centrally disposed depending hub thereon; a flat fuse element carried in said depressions with. the medial portion tting onto and around said hub, and with the ends fitting into the sloping sockets, said fuse elements being carried at right angles to the axis of the said base and being adapted to rotate therearound with the hub engaging the semi-spherical spring contact and with the fuse engaging spring contact and locking lug engaging a single element of said fuse within a single depression to make contact therewith and to prevent rotation in one direction; and means to secure a flange on the glass cover to a ange on the base to hold the spring contacts in rigid Contact with the hub and one of said fuse elements, substantially as described.

CLARENCE I. J USTHEIM. 

